The formal complaint follows an initial letter from Georgia and Alexandra Pryce to the PCC, which was copied to editors, journalists and MPs, protesting after the Daily Telegraph and Daily Mail used photographs of Pryce walking outside at East Sutton Park open prison in Kent taken by a press agency photographer. Both titles used pictures on their websites on Wednesday and then in their print editions on Thursday.

The daughters' letter noted that the prison had no shielding walls or fences, saying: "Are all at the prison to be punished by hiding from photographers until the Daily Telegraph tires of stalking its prey? A prisoner remains a human being with some rights to privacy from the Peeping Toms of the Telegraph."

It added: " Staff and prisoners have expressed concern about the photographers patrolling the prison perimeter, and we do not want their anger turned against our mother ... We have no views on the current row over press regulation but as citizens we are ashamed that a British newspaper should seek to humiliate a grandmother in the way it has in breach of the PCC request. Little wonder that there is an overwhelming public demand for a press that has some ethical norms."

While both titles used the photos the PCC spokesman said the complaint was made only against the Telegraph. There was no response from either newspaper or from Vicky Pryce's solicitor.

Separately the attorney general, Dominic Grieve, has rejected an MP's call to increase the eight month sentences imposed on Pryce and Huhne.

Responding to a letter from the MP, who said the terms were "unduly lenient", Grieve said he did not believe the appeal court would realistically increase them.